Block internal_stats in ROCKSDB_LITE

Summary: Block internal_stats in ROCKSDB_LITE.

Test Plan: make OPT=-DROCKSDB_LITE shared_lib

Reviewers: ljin, igor

Reviewed By: igor

Subscribers: dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D29541
[RocksJava] Support for stored snapshots

Summary:
RocksDB supports two ways of saving snapshots. In
memory and on disk. The later was added with this
pull request to RocksJava.

Test Plan:

Reviewers:

Subscribers: